Rapid Evaluation of the Mechanism of Buchwald-Hartwig Amination and Aldol Reactions Using Intramolecular 13 C Kinetic Isotope Effects.
| Autor: | Wambua V; Department of Chemistry, Binghamton University, Binghamton, New York 13902, United States., Hirschi JS; Department of Chemistry, Binghamton University, Binghamton, New York 13902, United States., Vetticatt MJ; Department of Chemistry, Binghamton University, Binghamton, New York 13902, United States. |
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| Jazyk: | angličtina |
| Zdroj: | ACS catalysis [ACS Catal] 2021 Jan 01; Vol. 11 (1), pp. 60-67. Date of Electronic Publication: 2020 Dec 11. |
| DOI: | 10.1021/acscatal.0c04752 |
| Abstrakt: | A practical approach is introduced for the rapid determination of 13 C kinetic isotope effects that utilizes a "designed" reactant with two identical reaction sites. The mechanism of the Buchwald-Hartwig amination of tert -butylbromobenzene with primary and secondary amines is investigated under synthetically relevant catalytic conditions using traditional inter molecular 13 C NMR methodology at natural abundance. Switching to 1,4-dibromobenzene, a symmetric bromoarene as the designed reactant, the same experimental 13 C KIEs are determined using an intra molecular KIE approach. This rapid methodology for KIE determination requires substantially less material and time compared to traditional approaches. Details of the Buchwald-Hartwig amination mechanism are investigated under varying synthetic conditions, namely a variety of halides and bases. The enantioselectivity-determining step of the l-proline catalyzed aldol reaction is also evaluated using this approach. We expect this mechanistic methodology to gain traction among synthetic chemists as a practical technique to rapidly obtain high-resolution information regarding the transition structure of synthetically relevant reactions under catalytic conditions. Competing Interests: The authors declare no competing financial interest. |
| Databáze: | MEDLINE |
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